Stitch-forming mechanism for sewing-machines



J. R. MOFFATT.

STITCH FORMING MECHANISM FOR SEWING MACHINES.

APPLICAHON HLED JUNE 16. 1915.

1 ,350, 326, Patented Aug. 24, 1920.

3 SHEE S-SHEET l.

Jl R. MOFFATT. STITCH FORMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JUNE 16, I915. 1,350,326. I Patented A g. 24, 1920.

3 SHEETSSH EET Z- throw;

J. R. MOFFATT. STITCH FORMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JUNIE 1 5. 19|5.

Patented Aug. 24, 1920.

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Q/vbbmaooao UNITED STATES 'P-ATENT OFFICE}.

JAMES R. MOFFATT, or onrcAe nnmors, ASSIGNOE TO Union SPECIAL MACHINE COMPANY, or CHICAGO, ILLINOIS, aCo-mmnATIoN OF ILLINOIS.

STITCH-FORMING MECHANIsM ronsnwmmlvmcnmns.

Specification of Letters Patent. Patented Allg 24 1920 Application filed June 16, 1915. Serial No. 34,426.

To all whom it may concern Be it known that I, JAMEs R. -Mormrr, a citizen of the United States, residing at Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Stitch-Forming Mechanism for Sewing-Machines, of which the following is a description, reference being had to the accompanying drawing and'to the figures of reference marked thereon.

The invention relates to new and useful improvements in stitch forming mechanism for sewing machines, and more particularly to a cross thread laying'mechanism coop crating with the needles above the work support.

An object of the invention to provide a cross thread laying mechanism having a thread guiding eye movable in a direction parallel to the line of feed and athread hook operating in front of theneedles and in a path at rightangles to the line of feed, with means for operating both of said. -el.e-' ments from a vertical shaft mounted in the supporting head for the presser bar and needle bar.

A further object of the invention is to provide a construction of the above character, wherein the vertical shaft also serves the purpose of an auxiliary presser bar to prevent the main presser bar from oscillating in its bearings.

These and other obvious and will in fully disclosed. i

In the drawings which show by way of illustration one embodiment of the invenobjects will in part be tion,- v

Figure 1 1s a rear new of a sewing machine having' my improvements applied thereto; Fig. 2 is an end elevation. certain of the parts. being omitted to avoid confusion;

Fig. 3'is a view partly in end elevation and partly in section, showing a part of the supporting head of the overhanglng arm, the feed, one of the needles. the looper, the

work support and the relation of fmy imimmediate mechanism for actuating the thread hook;

ciprocates.

part be hereinafter more 1 cooperates j the Fig. 5 is a detail showing the supporting bracket for the bar which supports the thread guide;

Fig. dis a detail showing in plan the Fig. 7 is a View partly in section showing one of the arms for preventing the presser bar from turning and its relation to the operating shaft for the cross thread laying mechanism;

Fig 8-"is a detail showing diagra atically the cross threads and the manner of holdlng the same for the needles; Flg. 9 is a detail showingone position of the controllingeyes for the cross thread and 1 Fig. 10 is a similar view showinganother position of the movable thread eye. I I The sewing machine to'which my inventionis applied consists of a supporting bed 1, "carrying a standard '2, on which is mounted an overhanging arm Said overhanging arm has a supporting head 4-'at its forward. end, in which the needlebar 5 rev Said needle bar 5"carries the needles (Sand '7. Said needle bar isrecipro catedin the usual way from a needle lever mounted in the overhanging arm.

The bed plate also provided with a work support 8 beneathwhich operates the feed dog 9. Thisfeed dog'is of the usual character and further description thereof is not thought necessary. Cooperating with the feed dog is a presser foot 10 which is carried by a presser-bar 11. The presserba'r 11 is mounted in the supporting head 4and' may be raised by a-hand lever 12 or a foot controlle'dlever 13.

Cooperating W113i) the needle is a cross reciprocate in bearings 1717 ina'bracket 18, which is clamped to the presser bar 11. The hub of'the bracket has projecting ears 19 through which a "clamping bolt 20 extends for causing-thehub to grip the presser bar. The supporting bar 16 for the thread guide 14 reciprocates in the bearings 17 and its direction of reciprocation is substantially parallel with the line of feed. "Said bar 16' c ries a collar 21 onitsfQrward-endand ingframe 28. The rocking frame 28 has a hub which freelyengages the presserbar 11". Said rocking frame at the opposite side from the connection of the'link'27, has a projecting arm carrying a pin 29 to which is. pivoted a link 30. The othermfend of the link30 is pivoted to an arm 31 which is clamped to and adjacent the lower end of the auxiliary presse'r guide bar 32.- This auxiliarypresser bar 32 is'mounted to oscillate, so that it may be movedendwisein.

bearings 34'and 35. Themain p'resser'bar has-a guide arm 36 fixed thereto and this arm projects:rea-rwardly and is. forked $37, so as to engage ablock 38 freely journaled on the auxiliary ipresser bar. A collar 39 is fixed to the auxiliar above said arm 36. hen the mainpres'ser bar 11 is raised this arm ,36 liftsthe'auxiliary 'presserbar 32. Said auxiliary presser bar, however, is free to-oscillate in its sup 9 auxiliary presser bar, which-becomes a ver-K porting bearings, as abovedescribed'. There is a' second guiding arm 40 at the upper end of the auxiliary presser bar, which is some what similar in'construction tothe arm 36; The auxiliarypresser bar 32 has a laterally projecting arm carrying a'ball' stud 41. A link 42 cooperates with this ball stud at one end and at the other end with a ball stud carried by an arm 43; which in turnis fixed tothe shaft 44. The shaft 44 is mounted to oscillate in" bearings 45 and 46. on the overhanging arm." Said shaft carries a fixed collar 47 which is provided with anjarm 48 carrying a ball stud ithwhich an eccentric: strap 49 ooperates. This eccentric strap 49 in turn cooperates with an eccentricouthe ain shaft 50. As the=main shaft-5O rotates the shaft 44 will be oscillated and-this will in turn, throughthe link 42,oscillate the tical shaft for oscillating the rocking frame 28, and as the rocking frame 28 oscillates the bar. 16-will be reciprorated, so as to' move the thread guide14 back and forth in a direction parallel with the line of feed.

-The thread hook '15 hasa' shank 51; which is mounted inan arm 52 ofarocking frame 53, which'is freely mounted on the presserbar. 11' beiow the rocking frame 28'. This rocking frame 53. has ajsecond arm 54, which is co'nnected by a link 55 to an arm56' the fabric.

presser bar, directly iliary presser bar 32 will, tl1erefore,also be imparted to the rocking frame 53 and this will move the thread hook 15 back and forth in front of the needles and in a direction needles for joining the needle loops beneath Thethread guide 14 and the thread hook 15 are each given a complete reciprocation for each complete reciprocation of -the needles, so that a loop is formed in the cross thread for each reciprocation of the needles; In Fig. 8 of thedrawings,

v 7 are preferably set so i that a single looper 57 cooperates with both I have shown diagrammaticallyt-he stitches as they appear on the upper face of" the fabric. 'Said stitches consist of the needle threads a and brand the cross threadc. WVhen the needles are at the upper end of their strokethe thread guide 14 is at the extreme rear end of its stroke andis just in rear of theneedle 7., At this time thethread hook-15 is atthe left-handof its stroke and a loop has been'forme'd in the cross thread 0. One strand of this loop extends :in rear of both needles 6 and 7 to the previous'intere locking ofthe cross thread'with the stitches. The other strandT-of this 'loop' extends. from the hook bet-ween'the needles to the thread 7 which has been formed thereby, the thread guide moves forward to'aposition in front of the needles and the hook againfengages the cross thread-for'forming a new loop.- As thethread guide 'movesforward the guiding eye 23 moves forward away from. the'thread guiding eyes '24 and25, as clearly shown in Fig 10, and this will pull off thread from,

the supply, so that when the hoolrmoves' to form its loop, the. eye 23 will give lip thread thereto. a

From the above description,it will parent that I haveprovided across thread laying mechanism, "wherein both: the'thread guide and the thread laying'hook are. posi tively actuated from a single verticalshaft mounted in {the supporting head for the needleb'ar'and thepresser-bar, and, there fore," the vibrating parts are substantially short and free from 'lateral vibrations, so

that the machine is capable ofhigh speedstitching; Itwill also be obvious thatI have been able to utilize the auxiliary presser bar for imparting movements tothe cross thread laying devices and have 'thereby :greatly simplified the construction of the machine.

It will also be noted that thelthread guide and the thread hook are supported bypand movable with the presser bar thereby-preventing interference with the presser foot, should the latter be raised at any time.

It is obvious that minor changes in the details of construction and arrangement of parts may be made without departing from the spirit of the ii'ivcntion' as set forth in. the appended claims. 1 I

Having thus described my invention, whatI claim as newand desireto secure by Letters Patent, is:

1. The combination with a work support, a feed, a presser foot, a main presser bar, needles, and complementa-l stitch forming mechanism, of across thread laying mechanism including a thread guide movable in a direction substantially parallel with the line of feed, a thread hook co6pcrating therewith, an auxiliary presser bar movable up and down with the main presser bar, means for oscillating said auxiliary presser bar, and devices operated by said auxiliary presser bar for actuating said thread guide and said thread hook.

2. The combination with a work support, a feed, a presser foot, a main presser bar, needles and complemental stitch forming mechanism, of a cross thread laying mechanism including a thread guide mounted to move bodily back and forth in a direction parallel with the line of feed, a thread hook mounted to oscillate about the axis of the presser bar, a shaft, means for oscillating said shaft, and devices for connecting said shaft to said thread guide and said thread hook for operating the same. v

3. The combination with a Work support, a feed, a presser foot, a main presser bar, needles and complemental stitch forming mechanism, of a cross thread laying mechanism including a thread guide, a bracket mounted on the presser bar and movable up and down therewith, a bar reciprocating in said bracket and carrying said thread guide,

means for reciprocating said bar,- a threadhook coo'perating with saidthread guide, means for pivotally supporting said thread hook on the presser bar, and means for os-. cillating said thread hook.

4. The combination with a work support, a feed, a presser foot, a main presser bar, needles and complemental stitch forming mechanism, of a cross thread laying mechanism including a thread guide, a bracket fixed to the presser bar and having spaced arms, a rod sliding in said arms and carrying said thread guide, a horizontally oscillating rocker arm mounted on'the presser bar, a link for connecting the rocker arm to said rod, and means for oscillating said rocker arm.

Thecombination with a work support, a feed, a presser foot, a main presser bar, needles and complemental stitch forming mechanism, of a cross thread laying mechanism including a thread guide, a bracket fixed to the presser bar and having spaced arms, a rod sliding in said arms andcarrying said thread guide, a rocker arm mounted on the presser bar, a link for connecting the rocker arm to said rod, an auxiliary presser-bar, means for oscillating the same, an arn'rcarried bysaid auxiliary presser bar, and a link for connecting said arm to the rocker arm on the main presser bar.

.6. The combination with a work support, a feed, a presser foot, a main presser bar, needles and complemental stitch forming mechanism, of a, cross thread laying mechanism including a thread guide,a bracket fixed to the presser bar, and having spaced arms, a rod sliding in said spaced arms and carrying said thread guide, means for reciprocating said rod in a direction substantially parallel with the line of feed, a second thread guide carried by said rod, stationary thread guides cooperating with the thread guide on said rod for pulling off and giving up cross thread to the first-named thread guide, and an oscillating thread hook coop-' crating with said first-named thread guide.

7. The combination with awork support, a feed, a presser foot, a main presser bar, needles, and complemental stitch forming mechanism, of a cross thread laying mechanism including a thread guide movable in a direction substantially parallel with the line of feed, a thread hook cooperating therewith, an auxiliary presser bar, means for oscillating said auxiliary presser bar, and devices operated by said auxiliary preser bar for actuating said thread guide and said thread hook. V

8. The combination of a work support, a feed, a presser foot, a main presser bar carrying said presser foot and cross stitching mechanism including a thread guide movable in a direction substantially parallel with the line of feed, a thread hook cooperating therewith and movable'in a direction substantially at right angles to the line of feed, means for supporting said thread hook and said thread guide on the presser bar whereby the same are moved up and down therewith through the action of the by the auxiliary presser bar and movable up and down therewith for actuating the thread hook and thread guide. I v

10. The combination of a work support, a

presser bar, a presser foot carried thereby and cross stitch mechanism including a thread guide, a thread hook cooperating therewith, means for supporting said thread guide and thread hookon said presser bar, an auxiliary presser bar and means carried by the auxiliary presser bar and movable up and down therewith for actuating the thread hook and thread guide, and means for controlling the thread of the thread guide,

11. The combination of a work support,

a presser bar, a presser foot carried thereby and cross stitch mechanism including a thread guide, a thread hook cooperating therewith, means for supporting said thread guide and thread hook on said pr'esser bar, an auxiliary presser bar and means carried by the auxiliary presser bar'and movable up and down therewith for actuating the thread hook and thread guide, devices carried by the supporting means for the thread guide for controlling the thread of said thread guide. 7

In testimony whereof I aflix my signature in the presence of two witnesses. V

, JAMES R. MOFFATT. Witnesses:

S. GEORGE TATE, V A. F; BREDSHALL. M j 

